A subject information acquiring device which has: an light absorbing member provided outside a subject; a light source radiating pulsed light on the subject and the light absorbing member; a detector detecting an acoustic wave produced from the subject and the light absorbing member by means of the pulsed light; and a signal processing unit acquiring subject information using a detection signal, and the signal processing unit calculates a second detection signal by specifying a signal resulting from an acoustic wave produced from the light absorbing member in a first detection signal, acquiring impulse response data using the specified signal, and deconvoluting the first detection signal using the impulse response data, and acquires the subject information using the second detection signal, can reduce image deterioration due to probe characteristics even when an impulse response of a probe is not measured in advance in a photoacoustic tomography.